Feng Li, Liu Junyang, Xu Chuang, Lu Wencong, Li Dongmei, Zhao Chuanliang, Liu Bingzhi, Li Xiang, Khan Sarfaraz, Zheng Huaili, Sun Yongjun
School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China.
School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China.
Sci Total Environ. 2019 Nov 1;689:546-556. doi: 10.1016/j.scitotenv.2019.06.475. Epub 2019 Jun 28.
As one of the core technologies employed in the field of sludge conditioning, flocculation has the ability to improve the sludge dewatering performance and reduce its volume and amount, which can accordingly result in lower costs in sludge transportation as well as subsequent disposal. Therefore, the development of new and high-efficiency flocculants is a hot topic in this field. The template copolymer (TPAD) of acryloyloxyethyl trimethyl ammonium chloride (DAC) and acrylamide (AM) was successfully synthesized through ultrasonic-template copolymerization using sodium-polyacrylate (NaPAA) as a template. The analysis of FTIR, H (C) NMR, TG/DSC and SEM revealed that TPAD had a conspicuously significant cationic segmental structure. In addition, the results obtained from the analysis on the association constant (K) and the kinetics of the template reaction indicated that the ultrasonic-template was a free radical initiated polymerization and the polymerization mechanism was I Zip-up (ZIP), and which once again confirmed the formation of the cationic fragment structure. This novel cationic fragment structure in TPAD greatly enhanced the ability of charge neutralization, electric patching, adsorption and bridging, thus improving the active sludge conditioning and dewatering performance (FCMC: 72.9%, SRF: 4.0 × 10 m·kg, d: 228.604 μm, D: 2.02 at 400 r/min). The floc breakage and regeneration experiments showed that the cationic fragment structure in TPAD could make great contribution to the formation of large and dense floc structures, and these flocs were able to regenerate rapidly after breakage. Finally, it was also known that these large and compact floc structures were beneficial to the creation of more channels and voids, thereby decreasing sludge resistance (SRF) and improving sludge dewatering performance.
作为污泥调理领域采用的核心技术之一，絮凝能够改善污泥脱水性能，减小其体积和数量，从而降低污泥运输及后续处置成本。因此，新型高效絮凝剂的研发是该领域的热点话题。以聚丙烯酸钠（NaPAA）为模板，通过超声模板共聚成功合成了丙烯酰氧乙基三甲基氯化铵（DAC）与丙烯酰胺（AM）的模板共聚物（TPAD）。傅里叶变换红外光谱（FTIR）、氢（碳）核磁共振谱（H（C）NMR）、热重/差示扫描量热联用仪（TG/DSC）及扫描电子显微镜（SEM）分析表明，TPAD具有明显的阳离子链段结构。此外，缔合常数（K）及模板反应动力学分析结果表明，超声模板聚合为自由基引发聚合，聚合机理为拉链式（ZIP），再次证实了阳离子片段结构的形成。TPAD中这种新型阳离子片段结构极大地增强了电荷中和、电补丁、吸附及架桥能力，从而改善了活性污泥调理及脱水性能（自由水含量：72.9%，比阻：4.0×10¹² m/kg，d：228.604 μm，400 r/min下的D值：2.02）。絮凝体破碎与再生实验表明，TPAD中的阳离子片段结构对形成大而致密的絮凝体结构有很大贡献，且这些絮凝体破碎后能够快速再生。最后还发现，这些大而紧密的絮凝体结构有利于形成更多的通道和孔隙，从而降低污泥比阻（SRF），提高污泥脱水性能。
